A wireless network is a common type of computer network that incorporates two or more devices capable of communicating wirelessly. The prevalence of wireless devices has grown exponentially with the adoption of mobile phones and other types of personal and consumer electronics, i.e. smart phones, tablets, netbooks, laptop computers and other wireless electronic devices.
The growth of wireless networking has grown in parallel with the adoption of Wi-Fi™, the series of wireless local area network (wireless LAN/WLAN) protocols based on the series of Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards. The adoption of Wi-Fi™ has allowed LANs to be deployed economically without the need to run cables, reducing costs and increasing flexibility. Furthermore, high adoption has increased the appetite for wireless data and created a market for faster networks with increased speed and capacity.
Worldwide Interoperability for Microwave Access (WiMAX) is a next generation wireless protocol introduced by the WiMAX Forum. WiMAX refers to a specific type of the series of interoperable IEEE 802.16 standards which are incorporated herein by reference. WiMAX offers increased speeds and improved range over WLANs utilizing Wi-Fi™, and supports fixed, nomadic and mobile deployments. Furthermore, companies have employed the standard to provide mobile broadband across large geographical areas and to compete with third generation mobile technologies, such as Global System for Mobile Communications (GSM) and Code Division Multiple Access (CDMA). WiMAX is often considered as an economical alternative to last mile Internet access currently served by cable or digital subscriber lines (DSL). The flexible bandwidth allocation and multiple built-in types of Quality-of-Service (QoS) support in the WiMAX network allow for deployments that include high-speed Internet access, Voice Over Internet Protocol (VoIP) and video calls, multimedia chats and mobile entertainment.
The IEEE 802.16 series of standards provide the air interface for a number of wireless communication standards, but does not necessarily define a standard WiMAX network. However, the WiMAX Forum's Network Working Group (NWG) has identified a standard set of end-to-end requirements, architecture and protocols for WiMAX, using IEEE 802.16e-2005 as the air interface. According to a WiMAX standard, the overall network may be logically divided into three parts: Consumer Premises Equipment (CPE), the Access Service Network (ASN) and the Network Operations Centre (NOC).
Consumer Premises Equipment (CPE) are devices used by the end user to access the WiMAX network. In fixed deployments, the CPE may be a WiMAX access point used to provide users with access to the WiMAX network through standard fixed or wireless LANs (e.g. using Wi-Fi™). In other embodiments, the CPE may be a mobile phone, a computing device or the like, able to access the WiMAX network directly when in range of a base station.
A Network Operations Centre (NOC) provides connectivity to the Internet, Application Service Providers (ASP), other public networks, and corporate networks. According to conventional WiMAX networks, the NOC also includes Authentication, Authorization and Accounting (AAA) servers that support authentication for the devices, users, and specific services. The NOC also provides user policy management of QoS and security and NOC is also responsible for IP address management, support for roaming between different NSPs, location management between ASNs, and mobility and roaming between ASNs. As WiMAX was developed at least in part to support the next generation of mobile devices, the NOC is also capable, in some implementations, of communicating with the Public Switched Telephone Network (PSTN) and 3rd Generation Partnership Projects (3GPP/3GPP2) via a Gateway and integrating Operations Support Systems (OSS) and Business Support Systems (BSS) within the NOC environment.
In prior art WiMAX architectures, communication between an ASN and both the CPEs and NOC is segregated. On the subscriber side, the ASN is operable to communicate with the CPEs using a base station. On the network side, communication between the NOC and the ASN occurs through an ASN Gateway (ASNGW). Data received at the ASN from a CPE via a base station will be passed to the ASNGW for proper message forwarding. The ASNGW of the prior art devices may communicate with the NOC to retrieve message forwarding instructions. As an ASN may cover a large geographic area, multiple base stations may be grouped within a single ASN, with one or more ASNGWs managing and tracking the flow of data amongst several base stations which may create unpredictable latency.
The WiMAX standard supports both Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD), although the widely deployed WiMAX Release 1 based on IEEE 802.16e technology only supports TDD as the duplexing mode. In any event, TDD is better positioned for mobile Internet devices where data transmission is asymmetrical.
TDD provides full duplex communication over a communication link applying time-division multiplexing (TDM). This form of implementation is simpler and cheaper than one utilizing FDD, as transceiver designs for TDD implementations are less complex and therefore less expensive. The uplink and downlink data rates between BS and CPE are managed by the scheduling algorithm, which allocates recurrent timeslots. Outbound transmissions from the BS are broadcast in addressed frames. Each CPE can then pick off those frames addressed to it. Accordingly, the dynamic allocation of traffic over a single communication link can be optimized based on load usage. In other words, capacity can be added or taken away from specific CPEs as the traffic loads fluctuate.
In conventional WiMAX networks, the base station (BS) will control access to the channel. Users wishing to transmit inbound to the BS must first send a request on a contention-based access channel. Exclusive permission to use the inbound traffic channel is then allocated by the BS using a system of transmission grants. Each CPE is allocated a transmission slot in time-frequency domain, thus there are no collisions.
Multicast is a form of one-to-many distribution. With similarities to broadcasting, multicasting allows a source to transmit a message to many receivers simultaneously. However, a difference between broadcasting and multicasting is that multicasting may limit the pool of receivers to those that are identified as part of the receiver group.
Multicasting is used in situations where a message needs to be sent to many receivers from a single transmission source. Instead of individually packaging a message for each individual receiver, the transmission source utilizing multicasting may send the message once. Common applications for multicast include the deployment of streaming media, such as Internet radio and television programs.
However, the prior WiMAX networks suffer from the disadvantage that any CPE-to-CPE multicast transmissions must be managed by and routed from the Access Network even for the CPEs that are behind the same Base Station.